Fast Facts

Members of the British parliament have strongly voted to renew the country's ageing nuclear weapons system, a multibillion-dollar project regarded as key to maintaining the country's status as a world power following its vote to leave the European Union.

Despite opposition from the pro-independence Scottish National Party (SNP) and some in the opposition Labour Party, parliament approved the Scottish-based nuclear-armed Trident submarines by 472 to 117 votes.

In her first statement in parliament as prime minister on Monday, Theresa May said Britain needed to retain its nuclear deterrent, which had been an insurance policy for the country's security for nearly 50 years.

"What this country needs to do is to recognise that it faces a variety of threats and to ensure we have the capabilities that are necessary and appropriate to deal with each of those threats," May said before the vote to approve the manufacture of four new nuclear-armed submarines.

The Trident programme replaces the country's fleet of nuclear-armed submarines with four new vessels at an estimated cost of $54bn over the next 20 years.

May did not hesitate when a member of the opposition asked whether she would be willing to order a nuclear strike.

"Yes," May said.

'Nuclear-free world'

"The nuclear threat has not gone away; if anything, it has increased," May said, referencing a newly assertive Russia and a desire from countries including North Korea to acquire nuclear weapons in defiance of the international community.

May also said that while Britain has voted to leave the European Union, "we will not leave our NATO and European allies behind.

"We cannot outsource the grave responsibility we shoulder for keeping our people safe," she said, adding that scrapping the Trident submarine-based weapons system would be "a reckless gamble, a gamble that would enfeeble our allies and embolden our enemies."

Hans Blix backs Corbyn's call to scrap UK's Trident

Labour Party leader Jeremy Corbyn, a life-long nuclear disarmament campaigner, questioned the need for Britain to possess "weapons of mass destruction" and said the country should, instead, press for a nuclear-free world.

"I would not take a decision that kills millions of people, I do not believe the threat of mass murder is a legitimate way to go about dealing with international relations," said Corbyn, though many of his own party members voted in favour of replacing the nuclear weapons system.

Al Jazeera's Europe Correspondent Barnaby Phillips said the vote to renew the weapons system was important for May following Britain's recent decision to leave the European Union.

"Theresa May hopes that this vote will send a message to Britain's allies, all of which were so disappointed by the Brexit vote. She argues that Britain is still an outward-looking country; a major military power prepared to take on international responsibilities in a dangerous and unpredictable world," he said.

But, it also means that "the chilling logic of mutually assured destruction is still with us, more than a quarter of a century after the end of the Cold War," Phillips said.